Landscape analysis of soil methane flux across complex terrain

Abstract. Relationships between methane (CH4) fluxes and environmental conditions have been extensively explored in saturated soils, while research has been less prevalent in aerated soils because of the relatively small magnitudes of CH4 fluxes that occur in dry soils. Our study builds on previous carbon cycle research at Tenderfoot Creek Experimental Forest, Montana, to identify how environmental conditions reflected by topographic metrics can be leveraged to estimate watershed scale CH4 fluxes from point scale measurements. Here, we measured soil CH4 concentrations and fluxes across a range of landscape positions (7 riparian, 25 upland), utilizing topographic and seasonal (29 May–12 September) gradients to examine the relationships between environmental variables, hydrologic dynamics, and CH4 emission and uptake. Riparian areas emitted small fluxes of CH4 throughout the study (median: 0.186 µg CH4–C m−2 h−1) and uplands increased in sink strength with dry-down of the watershed (median: −22.9 µg CH4–C m−2 h−1). Locations with volumetric water content (VWC) below 38 % were methane sinks, and uptake increased with decreasing VWC. Above 43 % VWC, net CH4 efflux occurred, and at intermediate VWC net fluxes were near zero. Riparian sites had near-neutral cumulative seasonal flux, and cumulative uptake of CH4 in the uplands was significantly related to topographic indices. These relationships were used to model the net seasonal CH4 flux of the upper Stringer Creek watershed (−1.75 kg CH4–C ha−1). This spatially distributed estimate was 111 % larger than that obtained by simply extrapolating the mean CH4 flux to the entire watershed area. Our results highlight the importance of quantifying the space–time variability of net CH4 fluxes as predicted by the frequency distribution of landscape positions when assessing watershed scale greenhouse gas balances.

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Landscape analysis of soil methane flux across complex terrain

10.5194/bg-2017-518 ◽

2018 ◽

Author(s):

Kendra E. Kaiser ◽

Brian L. McGlynn ◽

John E. Dore

Keyword(s):

Environmental Conditions ◽

Methane Flux ◽

Time Variability ◽

Sink Strength ◽

Watershed Scale ◽

Ch4 Flux ◽

Creek Watershed ◽

Spatially Distributed ◽

Dry Down ◽

The Mean

Abstract. Relationships between methane (CH4) fluxes and environmental conditions have been extensively explored in saturated soils, while in aerated soils, the relatively small magnitudes of CH4 fluxes have made research less prevalent. Our study builds on previous carbon cycle research at Tenderfoot Creek Experimental Forest, Montana to identify how environmental conditions reflected by topographic metrics can be leveraged to estimate watershed scale CH4 fluxes from point scale measurements. Here, we measured soil CH4 concentrations and fluxes across a range of landscape positions (7 riparian, 25 upland), utilizing topographic and seasonal gradients to examine the relationships between environmental variables, hydrologic dynamics, and CH4 emission and uptake. Riparian areas emitted small fluxes of CH4 throughout the study (median: 0.186 µg CH4-C m−2 h−1) and uplands increased in sink strength with dry down of the watershed (median: −22.9 µg CH4-C m−2 h−1). Locations with volumetric water content (VWC) below 38 % were methane sinks, and uptake increased with decreasing VWC. Above 43 % VWC, net CH4 efflux occurred, and at intermediate VWC net fluxes were near zero. Riparian sites had near neutral cumulative seasonal flux, and cumulative uptake of CH4 in the uplands was significantly related to topographic indices. These relationships were used to model the net seasonal CH4 flux of the upper Stringer Creek watershed (−1.75 kg CH4-C ha−1). This spatially distributed estimate was 111 % larger than that obtained by simply extrapolating the mean CH4 flux to the entire watershed area. Our results highlight the importance of quantifying the space-time variability of net CH4 fluxes as predicted by the frequency distribution of landscape positions when assessing watershed scale greenhouse gas balances.

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COLONY OF THE FUNGUS Aspergillus oryzae AND SELF-AFFINE FRACTAL GEOMETRY OF GROWTH FRONTS

Fractals ◽

10.1142/s0218348x93000046 ◽

1993 ◽

Vol 01 (01) ◽

pp. 11-19 ◽

Cited By ~ 20

Author(s):

SHU MATSUURA ◽

SASUKE MIYAZIMA

Keyword(s):

Aspergillus Oryzae ◽

Environmental Conditions ◽

Fractal Geometry ◽

Nutrient Concentration ◽

Incubation Temperature ◽

Characteristic Exponent ◽

Growth Front ◽

Favorable Condition ◽

The Self ◽

The Mean

A variety of colony shapes of the fungus Aspergillus oryzae under varying environmental conditions such as the nutrient concentration, medium stiffness and incubation temperature are obtained, ranging from a homogeneous Eden-like to a ramified DLA-like pattern. The roughness σ(l, h) of the growth front of the band-shaped colony, where h is the mean front height within l of the horizontal range, satisfies the self-affine fractal relation under favorable environmental conditions. In the most favorable condition of our experiments, its characteristic exponent is found to be a little larger than that of the 2-dimensional Eden model.

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Étude du développement hétéroblastique chez quelques espèces du genre Medicago

Canadian Journal of Botany ◽

10.1139/b83-240 ◽

1983 ◽

Vol 61 (8) ◽

pp. 2212-2223 ◽

Cited By ~ 2

Author(s):

Catherine Damerval

Keyword(s):

Environmental Conditions ◽

Mean Value ◽

Annual Species ◽

The Mean ◽

Shape Changes

Seven foliar types were defined for the first leaf in the heteroblastic development of seven annual species of Medicago L. Among the species, M. aculeata and M. murex have a typical foliar form. There is no relation between the first leaf and the succeeding trifoliolate one. The shape changes of the middle foliole of the trifoliolate leaves during the development allowed to establish a foliar sequence whose mean length was used to suggest an evolutive hierarchy among the taxa. Five quantitative variables were analysed on the first and on the sixth leaf for stability according to environmental conditions; the two stable variables (L/l and L/Pl) have a best discriminant value for the first leaf than for the sixth one. However, intraspecific heterogeneity is high in both cases. A relation between the flowering precocity and the mean value of one of the sixth leaf's variables (that is, the ratio of the length to the width of the foliole limb) was demonstrated in four species only. The heteroblastic development not only allows to establish a relation between foliar stage and physiologic age, but it itself constitutes a very good taxonomic and systematic criterium; it allowed to identify the seven species studied.

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Evaluation of Genetic behavior of Sunflower (Helianthus annuus L.) As Effect by Planting Dates

Al-Qadisiyah Journal For Agriculture Sciences (QJAS) (P-ISSN 2077-5822 E-ISSN 2617-1479) ◽

10.33794/qjas.vol9.iss1.73 ◽

2019 ◽

Vol 9 (1) ◽

pp. 150-155

Author(s):

Abdullah F. Serheed ◽

Haider T. Hussein

Keyword(s):

Helianthus Annuus ◽

Correlation Coefficient ◽

Environmental Conditions ◽

Genetic Variance ◽

Planting Dates ◽

Environmental Variance ◽

Growing Seasons ◽

The Mean ◽

Phenotypic Variations ◽

Coefficient Stability

Afield experiment was carried out during the spring and autumn seasons of 2016 and 2017 in AL- Musaib city / 40 km north of Babylon Provence. Two hybrids of sunflower( shamus, French hybrid (Euroflor) were used to evaluate the performance of the two cultivars at both growing seasons as well as knowledge of genetic behavior by studying the genetic and phenotypic variations, heritability percent, genetic and phenotypic coefficient, stability and persistence of the two cultivars .The results showed significant differences of the studied traits, as the genetic genotype (Shamus) most of the characteristics, especially in yield for two seasons.The genetic variance was higher than the environmental variance for the two seasons indicating that the two cultivars followed the same behavior. The heritability percent the dominant sense was high for most of the traits. The genetic and phenotypic variations between the mean and the high were different for the two seasons, the correlation coefficient was significant, for both cultivars, indicating the appropriateness of the two genotypes for the country's environmental conditions.

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Groundwater monitoring at the watershed scale: An evaluation of recharge and nonpoint source pollutant loading in the Clear Creek Watershed, Iowa

Hydrological Processes ◽

10.1002/hyp.11440 ◽

2018 ◽

Vol 32 (4) ◽

pp. 562-575 ◽

Cited By ~ 6

Author(s):

Keith E. Schilling ◽

Matthew T. Streeter ◽

E. Arthur Bettis ◽

Christopher G. Wilson ◽

Athanasios N. Papanicolaou

Keyword(s):

Groundwater Monitoring ◽

Nonpoint Source ◽

Watershed Scale ◽

Pollutant Loading ◽

Creek Watershed

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Estimating spatially distributed soil water content at small watershed scales based on decomposition of temporal anomaly and time stability analysis

Hydrology and Earth System Sciences ◽

10.5194/hess-20-571-2016 ◽

2016 ◽

Vol 20 (1) ◽

pp. 571-587 ◽

Cited By ~ 11

Author(s):

W. Hu ◽

B. C. Si

Keyword(s):

Stability Analysis ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Spatial Patterns ◽

Watershed Scale ◽

Small Watershed ◽

Time Stability ◽

Spatially Distributed ◽

Space Variant

Abstract. Soil water content (SWC) is crucial to rainfall-runoff response at the watershed scale. A model was used to decompose the spatiotemporal SWC into a time-stable pattern (i.e., temporal mean), a space-invariant temporal anomaly, and a space-variant temporal anomaly. The space-variant temporal anomaly was further decomposed using the empirical orthogonal function (EOF) for estimating spatially distributed SWC. This model was compared to a previous model that decomposes the spatiotemporal SWC into a spatial mean and a spatial anomaly, with the latter being further decomposed using the EOF. These two models are termed the temporal anomaly (TA) model and spatial anomaly (SA) model, respectively. We aimed to test the hypothesis that underlying (i.e., time-invariant) spatial patterns exist in the space-variant temporal anomaly at the small watershed scale, and to examine the advantages of the TA model over the SA model in terms of the estimation of spatially distributed SWC. For this purpose, a data set of near surface (0–0.2 m) and root zone (0–1.0 m) SWC, at a small watershed scale in the Canadian Prairies, was analyzed. Results showed that underlying spatial patterns exist in the space-variant temporal anomaly because of the permanent controls of static factors such as depth to the CaCO3 layer and organic carbon content. Combined with time stability analysis, the TA model improved the estimation of spatially distributed SWC over the SA model, especially for dry conditions. Further application of these two models demonstrated that the TA model outperformed the SA model at a hillslope in the Chinese Loess Plateau, but the performance of these two models in the GENCAI network (∼  250 km2) in Italy was equivalent. The TA model can be used to construct a high-resolution distribution of SWC at small watershed scales from coarse-resolution remotely sensed SWC products.

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Multi-year effect of wetting on CH<sub>4</sub> flux at taiga–tundra boundary in northeastern Siberia deduced from stable isotope ratios of CH<sub>4</sub>

Biogeosciences ◽

10.5194/bg-16-755-2019 ◽

2019 ◽

Vol 16 (3) ◽

pp. 755-768 ◽

Cited By ~ 4

Author(s):

Ryo Shingubara ◽

Atsuko Sugimoto ◽

Jun Murase ◽

Go Iwahana ◽

Shunsuke Tei ◽

...

Keyword(s):

Water Saturation ◽

Methane Flux ◽

Interannual Variations ◽

Ch4 Emission ◽

Ch4 Flux ◽

Ch4 Production ◽

Year Effect ◽

Northeastern Siberia ◽

Order Of Magnitude ◽

Acetoclastic Methanogenesis

Abstract. The response of CH4 emission from natural wetlands due to meteorological conditions is important because of its strong greenhouse effect. To understand the relationship between CH4 flux and wetting, we observed interannual variations in chamber CH4 flux, as well as the concentration, δ13C, and δD of dissolved CH4 during the summer from 2009 to 2013 at the taiga–tundra boundary in the vicinity of Chokurdakh (70∘37′ N, 147∘55′ E), located on the lowlands of the Indigirka River in northeastern Siberia. We also conducted soil incubation experiments to interpret δ13C and δD of dissolved CH4 and to investigate variations in CH4 production and oxidation processes. Methane flux showed large interannual variations in wet areas of sphagnum mosses and sedges (36–140 mg CH4 m−2 day−1 emitted). Increased CH4 emission was recorded in the summer of 2011 when a wetting event with extreme precipitation occurred. Although water level decreased from 2011 to 2013, CH4 emission remained relatively high in 2012, and increased further in 2013. Thaw depth became deeper from 2011 to 2013, which may partly explain the increase in CH4 emission. Moreover, dissolved CH4 concentration rose sharply by 1 order of magnitude from 2011 to 2012, and increased further from 2012 to 2013. Large variations in δ13C and δD of dissolved CH4 were observed in 2011, and smaller variations were seen in 2012 and 2013, suggesting both enhancement of CH4 production and less significance of CH4 oxidation relative to the larger pool of dissolved CH4. These multi-year effects of wetting on CH4 dynamics may have been caused by continued soil reduction across multiple years following the wetting. Delayed activation of acetoclastic methanogenesis following soil reduction could also have contributed to the enhancement of CH4 production. These processes suggest that duration of water saturation in the active layer can be important for predicting CH4 emission following a wetting event in the permafrost ecosystem.

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Intertidal zonation and seasonality of the marine hydroid Dynamena pumila (Cnidaria: Hydrozoa)

Canadian Journal of Zoology ◽

10.1139/z02-146 ◽

2002 ◽

Vol 80 (9) ◽

pp. 1526-1536

Author(s):

Lea-Anne Henry

Keyword(s):

Environmental Conditions ◽

Temporal Dynamics ◽

Wave Exposure ◽

Tidal Range ◽

Bay Of Fundy ◽

Rocky Shores ◽

Four Seasons ◽

The Mean ◽

Highly Correlated ◽

Number Of Branches

The vertical zonation and temporal dynamics of the marine hydroid Dynamena pumila were assessed across a wave-exposure gradient on five rocky shores in the Bay of Fundy, Atlantic Canada. Hydroid abundance and occupancy (i.e., percentage occurrence in a quadrat) were measured in 0.25-m2 quadrats at eight vertical elevations for each site over four consecutive seasons. Hydroid abundance and occupancy were highly correlated (R2 = 0.877). Estimates of hydroid fertility (percentage of sexually reproductive colonies) and size (stem height and number of branches) were obtained in five quadrats at every elevation over the four seasons. Abundance peaked at about 37.562.5% of the mean tidal range, with maximum abundance at the site with moderate wave exposure. Abundance peaked during the summer and dropped dramatically over the winter, particularly at the more wave-exposed sites. Winter ice scour and unfavourable environmental conditions reduced hydroid abundance, fertility, and size during the winter. This study demonstrates dramatic shifts in the distribution, fertility, and size of a marine hydroid. The importance of wave action, ice scour, and seasonal changes in environmental conditions is highlighted to emphasize their roles in regulating intertidal hydroid communities on boreal rocky shores.

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In vivo measurement of the frame-based application accuracy of the Neuromate neurosurgical robot

Journal of Neurosurgery ◽

10.3171/2014.9.jns14256 ◽

2015 ◽

Vol 122 (1) ◽

pp. 191-194 ◽

Cited By ~ 37

Author(s):

Daniel von Langsdorff ◽

Philippe Paquis ◽

Denys Fontaine

Keyword(s):

Independent System ◽

In Vivo Measurement ◽

Stereotactic Frame ◽

Spatially Distributed ◽

The Mean ◽

Neurosurgical Robot ◽

Better Than ◽

Deep Brain

OBJECT The application accuracy of the Neuromate neurosurgical robot has been validated in vitro but has not been evaluated in vivo for deep brain stimulation (DBS) electrode implantations. The authors conducted a study to evaluate this application accuracy in routine frame-based DBS procedures, with an independent system of measurement. METHODS The Euclidian distance was measured between the point theoretically targeted by the robot and the point actually reached, based on their respective stereotactic coordinates. The coordinates of the theoretical target were given by the robot's dedicated targeting software. The coordinates of the point actually reached were recalculated using the Stereoplan localizer system. This experiment was performed in vitro, with the frame fixed in the robot space without a patient, for 21 points spatially distributed. The in vivo accuracy was then measured in 30 basal ganglia targets in 17 consecutive patients undergoing DBS for movement disorders. RESULTS The mean in vitro application accuracy was 0.44 ± 0.23 mm. The maximal localization error was 1.0 mm. The mean (± SD) in vivo application accuracy was 0.86 ± 0.32 mm (Δx = 0.37 ± 0.34 mm, Δy = 0.32 ± 0.24 mm, Δz = 0.58 ± 0.31 mm). The maximal error was 1.55 mm. CONCLUSIONS The in vivo application accuracy of the Neuromate neurosurgical robot, measured with a system independent from the robot, in frame-based DBS procedures was better than 1 mm. This accuracy is at least similar to the accuracy of stereotactic frame arms and is compatible with the accuracy required in DBS procedures.

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